SALT LAKE CITY — A federal judge wants to know whether Utah County's assertion that it would not prosecute the polygamous family featured in "Sister Wives" is a ruse to avoid a legal challenge of the state's bigamy law.

U.S. District Judge Clark Waddoups' blunt questions had a state attorney on his heels for much of a 45-minute hearing Wednesday as he tried to defend Utah County Attorney Jeff Buhman's recent policy change regarding the statute.

"Is the act of the Utah County attorney simply an attempt to avoid the issue of what consenting adults can do constitutionally?" Waddoups asked assistant attorney general Jerrold Jensen.

In May, Buhman said in court documents that his office had adopted a formal policy not to prosecute the practice of bigamy unless it occurs in conjunction with another crime or if a party to the marriage or relationship is under 18.

The change came about 18 months after Buhman's office said it was investigating and might prosecute Kody Brown and his four wives under Utah's bigamy law. The Browns later filed a lawsuit, claiming the statute violates their constitutional rights to due process, equal protection, free exercise of religion, free speech and freedom of association.

Jensen contends that because the Browns won't be prosecuted, their lawsuit is moot and should be dismissed.

Calling it an "important issue to many people," Waddoups took the case under advisement and said he would rule as soon as possible.

The judge noted that other than in court documents, Buhman did not publicly announce the change and there's nothing to preclude him or a future county attorney from enforcing the law. "That goes to the sincerity of this policy," he said.

Jensen said Buhman, who did not attend the hearing, should be taken at his word.

"I don't think you can question the sincerity of the adoption of this policy," Jensen told the judge.

Jensen said after the hearing that he would call Buhman to the witness stand if the ruling goes against the state.

The Browns' attorney, Jonathan Turley, said the "faux" policy does not repeal the bigamy statute and that Buhman still considers it constitutional and enforceable. He never explains the reasons for not prosecuting people for bigamy, but is willing to do so if it's connected to another crime, Turley said.

"It's clearly an effort to avoid a ruling in this case," he said.

The law, Turley said, still "dangles like a Damocles sword" over the Browns.

Brown, who did not attend the hearing, filed a court declaration Tuesday saying despite the "policy" change, his family still feels threatened and that Buhman has never withdrawn his statements labeling them as criminals.

"We continue to suffer harm as a result of the criminalization of our plural family and the public attacks made against my family with reference to this law," he wrote.

Fearing prosecution, Brown moved his wives and then 16 children from Lehi to Nevada in January 2011. The Browns are finalizing the purchase of new homes and plan to stay in Nevada for the foreseeable future to avoid uprooting their children again.

In statement Wednesday, Brown said he remains committed to the lawsuit and that the people of Utah should have the final say on that question.

"While we continue our close ties to Utah, we have remained in Nevada in the best interest of our children and family," he said. "One of the factors weighing heavily on our decision has been the continued insistence of officials that this law is constitutional and that plural families are presumptive felons."

In court documents filed in May, Buhman denies making promises or threats to prosecute the Brown family.

"I never stated publicly that I would or would not prosecute the Browns," he wrote, "though I'm aware others in my office may have responded to the press to that effect."

The Browns sued Gov. Gary Herbert, Attorney General Mark Shurtleff and Buhman in July 2011. Waddoups earler dismissed Herbert and Shurtleff from the case.

In February, the judge ruled there was sufficient evidence to allow the Browns to pursue a lawsuit against Buhman contesting the constitutionality of the law.

Waddoups ruled that the Browns could only sue Buhman because his office made clear in media interviews that he intended to investigate and prosecute the Browns after the reality TV show "Sister Wives" debuted in September 2010.